code: def forward(ctx, x):
      ctx.save_for_backward(x)
      return x.log()
  
file_path: pyro/pyro/ops/special.py
imports: import functools
  import math
  import operator
  import weakref
  from typing import Dict
  import numpy
  import torch
  from numpy.polynomial.hermite import hermgauss
label_desc: Use image node_id 1 for calling the _SafeLog obj's underlying member method code with example usage: obj.forward(ctx, x) and returns: x